The present invention relates generally to a method of energy production, and more particularly, to an economical method for obtaining useful energy, e.g., electric power, from scaling or complex geothermal waters.
The utilization of geothermal waters throughout the world has been highly successful in only a few isolated instances, such as where a clean steam is available, or where a source of hot water or water-steam mixture is available with essentially no contaminants in the water. However, in the most common occurrences, geothermal waters are not sufficiently hot by normal steam power plant standards. Another problem is that the waters have a high content of soluble matter that tends to cuse scaling of heat exchange equipment, or by the flashing steam going to the turbines.
An extensive supply of relatively high temperature geothermal brines are found in some locations such as the Salton Sea region of California. These waters contain up to about 20% of dissolved solids. The geothermal brines possess such high temperatures and are located at such a distance below the earth's surface that they usually vaporize as the brines rise up through a pipe to the earth's surface. The resulting problems of scaling and corrosion of the pipe walls, in addition to the scaling volatile components in the steam, have caused turbines to become inoperable within periods as short as 4 to 6 hours. Further, the removal of such scale-forming constituents in the geothermal waters is exceedingly difficult. Attempts have been made to transfer the heat contained in the brine to a second fluid through conventional indirect heat exchange tubes. However, this process has suffered from the aforementioned problems of severe corrosion and difficult fouling of the tubes.